【精讲考点二】利率的分解
收益率的分解（Decompose required rate of return）指把利率看成实际的无风险利率、预期的通货膨胀、以及补偿投资者不同种类风险的风险溢价之和。

无风险利率（risk-free rate）指投资者在没有任何不确定因素的条件下能够获得的收益率。在现实中，我们一般把银行存款和短期国债当作是无风险的投资资产。投资者在市场上所能观察到的无风险利率都是名义无风险利率。

Decompose required rate of return
Decomposerequiredrateofreturn:
Required interestrate ona security = nominal risk-free rate+ default risk premium+ liquidity risk premium + maturity
risk premium
Realrisk-freerateandnominalrisk-freerate:
(1 + nominal risk-free rate) = (1 + real risk-free rate)(1 + inflation premium).
Inpractice,Nominal risk-free rate=real risk-free rate +inflation premium
The real risk-free rate reflects the time preferences of individuals for current
versusfuturereal consumption.Theinflationpremium compensatesinvestors
for expected inflation.
Many countries have short-term government debt whose interest rate can be
consideredtorepresentthenominalrisk-freeinterestrateoverthattime
horizon in that country.